Mineral oil composition



Patented Oct. 9, 1945,

RATENT' OFFICE MINERAL on. COMPOSITION John J. Giammaria as Orland M. Reifl, Woodbury, N. 1., assignors to Socony -Vacunm Oil Company, Incorporated, a corporation of New York No Drawing. Application May 21, 1943.

' Serial No. 488,742

I Claims. (01.252-323) This invention has to do in a general way with mineral oil compositions and is more particularly related to compositions comprised of mineral oil and a minor proportion of an added ingredient which will improve the oil in one or more important respects.

It is well known to those familiar with the art that mineral oil fractions refined for their various uses are in and of themselves usually deficient in one or more respects, so that their practical utility is limited even in the particular field for which they have been refined. For example, mineral oil fractions refined for use as lubricants have a tendency to oxidize under conditions of use with the formationof sludge or acidic oxidation products; also the lighter frac-- tions such as gasoline and kerosene tend to oxidize with the formation of color bodies, gum, etc. In order to prevent or retard the formation of these products and thereby extend the useful life of the oil fraction, it is common practice to blend with such oil fractions an additive ingredient which will have the effect of inhibiting oxidation, such ingredients being generally known to the trade as oxidation inhibitors or sludge inhibitors, gum inhibitors, etc.

It is also the practice to add other ingredients to form deposits which interfere with the function of the piston rings.

Aside from the corrosive action which attends the formation of acidic products of oxidation in mineral oil fractions of the lubricant range, it has been discovered that certain types of recently developed hard metal alloy bearing metals, such action.

In the lighter mineral oil fractions, such as those used for fuel purposes, particularly in internal combustion engines, it has been found that the combustion characteristics of the fuel may be controlled and improved by adding minor proportions of various improving agents thereto.

The various ingredients which have been developed for use in mineral oil fractions to imenumerated above are largely specific to their particular applications, and it has, therefore,

to mineral oilfractions for the. purpose of improving "oiliness characteristics and the wearreducing action of such mineraloils when they are used as lubricants, particularly when the oils are used for the purpose of lubricating metal surfaces which are engaged under extremely high hi'gh cylinder pressures, there is a decided tendency for the ordinary lubricating oil fraction to form, under such conditions of use, carbonaceous deposits which cause the piston 111188 to become stuck in their slots and which fill the slots in the oil ring or rings, thus materially'reducing the elliciency of the engine. Ingredients have, therefore, been 'develope'dwhich, when added to the oil, will reduce the natural tendency of the oil v of phosphorusprove such fractions in the various respects been the practise to add a separate ingredient for each of the improvements which is to be effected.

We have discovered that mineral oil fractions such as those referred to above can be improved in several of the various properties enumerated above by the incorporation therein of a small quantity of a m-ulti-functional compound or reaction product selected from a new and novel class and sulfur-containing compounds or reaction products. More specifically,

' we have found that the compounds or reaction products obtained by the reaction: of substantially two mols of alkyl-substituted hydroxyaromatic carboxylic acids and one mo] of phosphorus pentasulfide; and the metal salts thereof, improve such oil fractions in more than one of said properties. Particularly preferred, however, of these multifunctional oil addition agents are those compounds or reaction products of the aforesaid class which contain one orvmore oilsolubilizing "heavy alkyl groups, that is, aliphatic hydrocarbon groups of relatively high molecular weight preferably containing notless than 20 carbon atoms, in the aromatic nucleus or aromatic nuclei.

The multifunctional oil addition agents of this invention are referred to as compounds and as reaction products inasmuch as both definite com- 2 pounds and products of indefinite-chemical structure are obtained by reaction of substantially two mols of an alkyl-substituted hydroxyaromatic carboxvlic acid and one mol of phosphorus pentasulfide: On the basis of chemical analyses of the phosphorusand sulfur-containing products of this reaction, the principal product appears to be a combined thiophosphate esteraryl thiolic acid,

OP=S I, R,. -cosn and the most probable reaction mechanism is /OH /on -11. (a), 2Rn-T-OOOH'FP2SB; 2R..'rco 11+o,+msi

/OH /QP=S (b) 2R,.- T-cos11+0,+1 ,s; 2R.- -'r-cosH+m s whereinT is an aromatic nucleus, either monoor polycyclic, such as phenyl, naphthyl, anthracyl, etc.; R.is an oil solubilizing aliphatic hydrocarbon radical or group containing at least about 18 carbon atoms, and is preferably a high molecular weight derivative or a heavy alkyl group, and n is a small whole number, preferably 1 to 4. As aforesaid, also contemplated herein. are the metal salts of-the phosphorusand sulfur-containing compounds and reaction products obtained by reaction of two mols of the aforesaid carboxylic acids and one mol of P285, wherein a.

metal (M) replaces the hydrogen of the thiolic acid group, COSH. Thus, the metal salts of mixed thiophosphate ester-aryl thiolic acids may be represented by the following formula,

0 o-Pi wherein M represents at least one metal equivalent, and R and n are asdeflned above. As contemplated herein the metal salts-represented by Formula III, are inclusive of both the neutral I metal salts, wherein M will represent a metal atom such as -Na, -Ba--, etc., and the basic metal salts of said acids. In the latter salts, the symbol M, which represents at least one metal equivalent, is broadly construed to represent a basic metal grouping which is defined herein as apolyvalent metal atom having at least one valence satisfied by a hydroxide group or an alcoholate group, and having at least one valence satisfied as shown in Formula III. r

The metal substituent in the thiolic acid group of the oil-improving agents described herein may be broadly classified as follows: the alkali metals, lithium, sodium, potassium, rubidium and caesium; the alkaline earth group, beryllium, magnesium, calcium, strontium and barium; the metals' zinc, cadmium and mercury, scandium, yttrium, lanthanum, aluminium, gallium, indium, thallium, titanium, zirconium, cerium, thorium; germanium, tin and lead; vanadium, columbium and tantalum; arsensic, antimony and bismuth; chromium, molybdenum, tungsten and uranium; rhenium, manganese, iron, cobalt and nickel; ruthenium, rhodium and palladium; osmium, iridium and platinum.

Some of the rare earth metals are given in the above group of metals; other rare earths suitable for the formation of combined thiophos phate ester-aryl thiolic acid salts are those now 40. --COOX groups; X is hydrogen or at least one commercially available as the cerium and yttrium groups, namely, a. mixture of praseodymium, neodymium, Samarium, europium, gadolinium, terbrium; dysprosium, holmium, erbium, thalium, and lutecium. Particularly preferred metalsfor the salts contemplated herein are barium, tin and cobalt. The combined thiophosphate ester-thiolic acids and salts described above may also be characterized by another substituent group, or groups, on the aromatic nucleus. That is, in addition to the alkyl, thiophosphate ester (-OPOS) and thiolic acid (-COSH, or metal thiolate --COSM) groups on the aromatic nucleus, other nuclear hydrogen atoms may be replaced by a monovalent substituent, or substituents, selected from the group consisting of hydroxyl, metaloxy, alkoxy, aroxy, ester, aralkyl, alkaryl, aryl, alkyl, (such as short-chain groups, methyl, ethyl, etc., in addition to the preferred long-chain R groups), halogen, nitro and nitroso; all of these substituents will be hereinafter referred to as Y substituents. Still other Y substituents which may be present are those having a multiple valence and these include the monoand poly-sulfide-selenide and -telluride groups; of these groups, the disulfide group is particularly preferred. Thus the compounds containing a Y substituent, or substituents, uull be represented by the formula wherein Y is nuclear hydrogen or a group such as defined above; 1' is the numeral 0 or a small whole number, from 1 to 3, corresponding to the valences on the nucleus T not satisfied by R, --OPOS and metal equivalent and the symbols T, R and n are as defined hereinbefore.

It will be apparent that those compounds contemplated herein which contain a Y substituent having a multiple valance, such for example as a disulfide group, will be characterized by more than one combined thiophosphate ester-thiolic acid (or metal thiolate) aryl hucleus, and that such compounds wil1- be represented by the follow- .ing general formula the aforesaid monovalent substituents and multiv alent substituents and the group in which 2 is representative of the aforesaid multivalent substituents and thesymbols m, T, X, R. and n are as defined hereinabove.

As indicated above, the particularly preferred type of compounds or reaction products contemplated by the "present invention are those represented by Formula I, III and WM) and (b), in which the group represented by R is an aliphatic hydrocarbon radical of relatively high molecular weight, preferably containing not less than 20 carbon atoms. In the foregoing formulae (I, III and IV(a) and (b)) it will be observed that the allphatic or alkyl substituent in the aryl nucleus is a monovalent aliphatic hydrocarbon group, but, as will appear from the hereinafter described synthesis' of our preferred type of oil-improving agent, part or all of the aliphatic hydrocarbon material may be comprised of polyvalent aliphatic hydrocarbon radicals or groups in which the several valances are attached to separate aromatic nuclear groups. Compounds of this type are included under the following general formula rep resentation in which R, T, X, Y, 21, r and m have the same significance indicated above; R represents at least one oil-solubilizing aliphatic or alkyl radical or group, such alkyl group or groups being attached by one valance only to at least one aromatic nucleus T, 2: representing the valance of the aliphatic radical R which may be a small whole number from 1 to 4; and u represents a whole number from 1 to 4 and indicates the total number of groups equal to 2,- 3, or 4) and since R is defined as being at least one aliphatic radical or group and may therefore include'several such groups, it will be seen that the general formula V is inclusive of compounds having nuclear aliphatic groups or radicals of different valences (from 1 to 4) in the same molecule. Also it will be observed that since u may be any whole number from l'to 4, the number of aromatic nuclei T in said molecules may likewise vary from 1 to 4. It will be seen, therefore, that the relationship between u and v in formula V, in its broadest aspect, is such that when u is equal to l, v is equal to l; and when u is greater than 1, the valence '1: of at least one of the R's is equal to u (in order to tie the several nuclei or T's together), the valence of any remaining R's being any whole number equal to or less than u.

In the above general formula V, it will be understood that since the groups R are aliphatic hydrocarbon radicals of the chain type and are each attached by one valence only to each corresponding aromatic nucleus, the valence v of such radical or radicals is of necessity never number of aromatic nuclei in the molecules and in formula V is always equal' to 1 when u equals 1.

Otherwise an R," having a valence greater than the number (u) of aromatic nuclei would either have some of its valences unsatisfied or else would form a condensed ring or rings of attachment at two or more points to one and the same aromatic nucleus. Such latter compounds, as readily indicated from the definition of R, are not considered as characterizing the product of the present invention although probably formed in some instances in minor amounts as unobiectionable by-products by certain of the methods of tion herein disclosed.

The type of compounds coming under general formula V in which only the thiophosphate group (-0105). one thiolic acid group or metal thiolate group (COSX) and the oil-solubilizing group or groups (R?) are present on a monocyclic nucleus, are illustrated by the following formulae.

When v and u are each equal to l and one R group is present, the compounds are illustrated by preparain which the chains and X are as defined above.

Compounds of the type satisfying the general formula V in which R" is polyvalent and v and u are more than one and in which there is only one such polyvalent R" group, may be illustrated by the following formula, in which the aryl nucleus T is again indicated for illustration as being Under this same type of compound-indicated by formula C there may be more than one polyvalent R" group (represented by the chain), such a compound in which there are, for example. two

polyvalent R? groups being illustrated by the hydrogen in the aromatic nucleus T substituted following formula: -with predominantly aliphatic material which 11 u I H --c11 no H 0-1: 0-1: D --'-c0sx n at- 2 no "CH 11 n 11 Another possible molecular structure of comcomprises a sufllcient'proportion of the composipounds coming under formula V is that for a tion as a whole to renderthe same miscible with compound having more than one polyvalent R1: the mineral oil fraction in which the improving group, at least two of which have diiferent agent isused under normal conditions of hanvalences, such as the following: dllng and use. It appears from the results of our 11 H H H H With regard to the possible number of R" research that there is a critical range in the degroups which may make up a single molecule. this will vary to the extent to which it is desired which the product or agent will not satisfy the to eflect substitution of the nucleus with oilequirements for oil-miscibility. Expressing this solubilizing alkyl groups for obtaining the dein another way, it appears that the hydroxyarosired properties in the product and is, of course, matic constituent (T'0H), of the alkylated hylimited by the number of valences on the arodroxyaromatic ar xyli a id. fr m w h t matic nucleus which are available for substitu- Combined h OD D este -t e c ac d i detion. As will be apparent to those skilled in the rived should not exceed a certain per of art, the maximum possible number of R groups such alkylated hydroxyaromatic carboxylic acid. which can be attached to a single aromatic nu This critical range of alkylation may be roughly gree of alkylation of these improving agents below cleus will vary as the nucleus is monoor polyexpressed as the ratio by weight of (T(OH) )u to cyclic and also as the nucleus is otherwise sub- R (T(OH)).u.

stituted. It will also be apparent that available The de ree of alkyletion and the critical ran e valances on the nuclei may allbe attached to withinwhich operative or preferred compounds polyvale'nt aliphatic substituents. can be obtained may also be expressed as the It will be understood that the oil-improving number of carbon atoms contained in the aliagents contemplated by this invention may be phatic substituents for each aryl nucleus in a pure compounds satisfying the general Formula given c e 01 le lll Str cture.

V (and the general formulae I, III, and IV(a) The critical range inthe degree of alkylation, and described above with any one of the as defined above, of the aryl nucleus in the imvarious monoand polycyclic aromatic nuclei as p g agents contemplated herein may y I T and the various substituents R, (OPOS), with: (a) the mineral oil fraction in which the (COSX), (COOX) and Y described, the only improving agent is to be used; (b) the ary n requisite being that at least one nuclear hydrogen cleus T (monoor poly-cyclic) (c) the hydroxyl be substituted with a thiophosphate ester group, content of the aryl nucleus from which the thioanother nuclear hydrogen being substituted with p osphate ester substituent is derived (monoor a thiolic acid or metal thiolate group (COSX), poly-hydric); (d) the character of aliphatic maand at least one nuclear hydrogen be substituted terial comprising the IR") substituent (straight with an oil-solubilizing aliphatic radical or or branched chain); (e) monoor poly-substigroup (R However, in manufacturing thepretution of the aryl nucleusyand 0) other substitferred oil-improving product of the present in uents on the nucleus T, which may be of positive vention by the preferred method of procedure, as or negative or of neutral solubilizing activity. will appear hereinafter, the final oil-improving In general it may be said that a polycyclic nuproduct obtained is normally or usually a mixture cleus appears to require a higher degree of alkylaof different compounds corresponding to different tion than a mon y c s; that a p yhydric values of 12 and u and to different numbers of nucleus requires a higher degree of alkylation aliphatic groups R". It is for this reason that we than a monohydric nucleus; and that branchedhave designated the oil-improving agents conchain aliphatic substituents have a somewhat templated herein as compounds and as reaction greater solubilizing action than straight-chain products, and intend the designation "reaction solubilizing substituents.

products broadly to encompass the compounds In view of the foregoing variables it would be obtained herein. Y impracticable and probably misleading to attempt As has been emphasized hereinabove, it is imto give an expression and figure which would inportant that the preferred oil-improving agents dicate accurately the proper ratio of hydroxyas represented by general formula V have nuclear aromatic constituent to the alkylated hydroxyaromatic constituent which would express a degree of aliphatic substitution satisfying. all cases taking these variables into account. As a guide for preparing the improving agents of this invention, however, our research indicates that for a dex (V. I.) improving properties in addition to other valuable properties the ratio, expressed as:

weight of phenol. It will be observed that the ratio as expressed by Formula VI above does not take into account any other substituent in the nucleus than the aliphatic substituent and the hydroxyl group (which appears as a thiophosphate ester group in the final product), but since the aliphatic substituent is primarily relied upon as the solubilizing medium in the combined thiophosphate ester-thiolic acids (and salts thereof) derived from the aforesaid hydroxyaromatic'acids, it is believed that the foregoing expression and limits will serve as a working guide for the preparation of oil-soluble materials and particularly of the preferred multifunctional reactionproducts and compounds contemplated herein.

The ratio of 20 per cent, which we may term the "phenolic ratio, represents what we consider a maximum figure for the preferred products of this invention, and in general it will be found that this figure will be lower. The actual ratio, of course, depends upon the variable factors enumerated above. For example, as will appear here- .inafteryan oil-soluble combined thiophosphate wise unsubstituted should have a phenolic ratio, as expressed above, not substantially greater than about 16 per cent.

The degree of alkylation for these preferred multifunctional oil-improving agents may also be expressed by the number of carbon atoms contained in the aliphatic substituent for'a given product having pour depressing and viscosity in naphthyl methyl ether. chlorphenol and the like.

' Preference is given to the monohydroxy phenols otherwise unsubstituted, particular preference being given to phenol and alphaand beta-naphthol. h 1

As indicated in said patent (2,197,837), the alkylation of the hydroxyaromatic compound may 'be accomplished in variousways, such as by Friedel-Crafts synthesis using a halogenated aliphatic hydrocarbon; by reaction with unsaturated high molecular weight aliphaticcompounds or higher alcohols in the presence of a suitable catalyst such as sulfuric acid, etc. The l 'rie'del- Crafts type of alkylation reaction. howev'er, is particularly adapted to the preparation of the alkylated hydroxyaromatic compounds from which the corresponding acids are obtained because the Friedel-Crafts synthesis affords a convenient means of controlling the degree of alkylation and obtaining the desired phenolic ratio.

In this latter type of synthesis an appropriate monoor poly-chlorine-substituted aliphatic compound or material is reacted with the desired hydroxyaromatic compound in the presence of a skilled in'the art, it is usually difllcult to prepare hydroxy-aromatic nucleus T-OH. As a general guide in this connection it may be said that the substituents represented by R in the above general Formula V should, for these preferred compounds or reaction products, contain at least twenty carbon atoms for each aromatic nucleus.

The alkylated hydroxyaromatic carboxylic acids which are reacted herein with P285 in the molar proportion of 2:1 are preferably obtained by the procedures described in Patent 2,197,837,

issued for one of the present inventors, 0, M.

Reiff. As described therein, numerous hydroxyaromatic compounds may be used as the starting materials and alkylated, and thereafter carboxylated. Examples of the hydroxyaromatic compounds which may be used as starting materials characterizing molecules.-

or obtain high molecular weightaliphatic hydrocarbons in a pure or substantially pure state and correspondingly difiicult to prepare the chlorineor other halogen-substituted products in a pure or substantially pure state. -It is preferred, therefore, to employ a mixture of such halogenated hydrocarbons, such as halogenated petroleum fractions, as the starting material. In general it may be said that the high molecular weight aliphatic hydrocarbons contemplated aspreferred tively long hydrocarbon chain substituents. Special preference is given to petroleum wax having a melting point not substantially less than about -120 F. and having a molecular weight of about 300 and at least twenty carbon atoms in the Since the product of a Friedel-Crafts reaction between a chlorinated aliphatic materialof the type referred to above and a hydroxyaromatic compound will be a mixture of different values of v and u in the formula R" (T(OH) )u shown above in describing the "phenolic ratio, and the final thiophosphate ester-thiolic acids (and salts thereof) derived therefrom will likewise be a mixture of compounds corresponding to different values of v and u in general formula V, it will be understood thatthe specific values for v and u in the above formula as well as the general formula V relate to the different specific compounds present in such a mixture which characterize it as a reaction product of this invention.

Following alkylation of the desired hydroxyaromatic compound, the alkylated reaction product thus obtained is carboxylated according to the procedures outlined in Patent 2,197,837. As

indicated therein, one suitable procedure involves first forming an alkyl-substituted metal hydroxylate from an alkyl-substituted hydroxy-aromatic compound and a metal such as an alkali or alkaline earth, and then carboxylating the hydroxylate (obtained in the preceding operation) with carbon dioxide gas to form the alkylated hydroxyaromatic carboxylic acid. The latter product is available for reaction with P285 to provide the multifunctional oil-improving agents of this invention. Typical alkylated hydroxyaromatic carboxylic acids which maybe reacted with P285 as hereinafter described, include the carboxylic acids ,of the representative hydroxy-aromatic compounds enumerated above. Preferred herein are alkylated phenol and naphthol carboxylic acids.

In the event that an aliphatic material such as petroleum wax described above is used as the alkyl substituent on the hydroxyaromatic com-' pound and corresponding hydroxyaromatic carboxylic acid derived therefrom, and is reacted in the form or halogenated wax containing, for example, three atomic proportions of chlorine and 14 per cent chlorine, with one mol of said bydroxyaromatic compound, the alkylated hydroxyaromatic compound and the alkylated hydroxyaromatic carboxylic acid will be, for convenience, designated hereinafter as wax-hydroxyaromatic compound (ii-14) and "wax-hydroxyaromatic carboxylic acid (3-14), respectively. Parenthetical expression of the type (A-B) may be used hereinafter in connection with such compounds to designate (A) the number of atomic compound in the Friedel-Crafts reaction and (B) the chlorine content of the chloraliphatic material. In the above illustrations 11:3 and 13:14.

This same designation will also apply ,to the alkylated thiophosphate ester-thiolic acids,,and their metal salts, derived from these alkylated compounds. 1

The multifunctional phosphorusand sulfurcontaining oil improving agents of this invention are obtained by reaction of substantially two mols of an alkylated hydroxyaromatic carboxylic acid of the type described above and one mol of P285. They "may also be obtained by reaction of the alkali or alkaline earth metal salts of the aforesaid alkylated hydroxyaromatic carboxylic acid and P285 in the same molar ratio, but the preferred procedure is that one in which the metal-free carboxylic acid reactant is used. The procedures outlined above will be illustrated by the following examples, wherein reaction products typical of the aforesaid reaction products are prepared. Y

REACTION OF ALKYL-SUBSTITUTED HY- DROXYAROMATIC CARBOKYLIC ACIDS AND PzSs EXAMPLE 1 Reaction of wax-substituted phenol carboaylic acid and P235 (67 secs. S. U. V. at 120 F.) 100 Pass v 13.5 Ethylene dichloride 200 (6) Procedure:

The wax-phenol carboxylic acid in mineral oil blend, prepared according to the procedure in Patent 2,197,837, is mixed with P285, the mol ratio ot acid to Pass being about 2:1, in a reaction vessel equipped with stirrer and reflux condenser.

then filtered and the ethylene dichloride solvent" is distilled from the filtrate whereby the finished product, the combined thiophosphate esterthiolic acid of wax-phenol carboxylic acid is obtained in mineral oil. Chemical analysis of the product indicates that the formula, for such product is,

'R- COSH wherein R is wax.

EXAMPLE 2 Reaction of wax-substituted phenol carboayltc acid disulflde and P285 (a) Reaction mixture:

' Grams Wax-phenol carboxylic acid disulflde (3-14) in solution in 300,grams of mineral oil (67 secs. S. U. V. at 310 F.) ,PzSs 13.1 Ethylene dichloride 200 i (b) Procedure:

The reaction of wax-phenol carboxylic acid disulflde, obtained as described in co-pending application of Serial No. 330,532, filed by O. M.

Reifi on April 19, A940, now issued as Patent No.

2,319,189 of May 11, 1943, was carried out according to the procedure given in Example 1, and here again the molar ratio of the acid disulfide to P285 was about 2:1. The reaction product, in mineral oil blend, is believed to be the combined thiophosphate ester-thiolic acid of waxphenol carboxyllc acid disulflde and the formula wherein Ra is wax.

As aforesaid, the neutral and basic metal salts of the aforegoing reaction products are also contemplated by this invention. These metal-containing products are obtained by reaction of the combined thiophosphate ester-thiolic acids of the alkyl-substituted hydroxyaromatic carboxylic acids with alkali or alkaline earth metal alcoholates or hydroxides. In the use of the metal alcoholates, the thiophosphate ester-thiolic acid reaction product is diluted with one part of bu-, tanol, followed by adding the metal alcoholate, preferably as the metal ,butylate, heating the reaction mixture to the reflux temperature for one hour and then distilling off the alcohol-such as butanol-to obtain the finished product, the corresponding metalisalt. In the use 01' metal hy-f part of benzol, followed by adding the metal hydroxide. The reaction mixture is heated gently at the distillation temperature of benzolwhereupon the water of reaction is removed. Any hydroxide residue is removed by filtering the reaction mixture and then distilling oil the remain ing benzol from the filtrate to obtain the finished product.

Metal salts of the phosphorusand sulfurcontaining reaction products described above, other than those of the alkali or alkaline earth metals, are formed by double decomposition of an alkali or alkaline earth metal salt withan alcohol solution of the chloride of the desired metal. The general procedure consists of dissolving the metal chloride in butanol and slowly adding the butanol solution thus obtained to the alkali (or alkaline earth) metal salt of the thio-' phosphate ester-thiolic acid reaction product.-

The mixture thus formed is heated at the reflux temperature for about 30 minutes and the alcohol solvent is then distilled oil. The solvent-free mixture is then filtered through a suitable filter medium such as Hi-F'low to remove alkali (or alkaline earth) chloride formed as a by-product; the filtrate is the finished metal salt of said reaction product.

The alcoholate method -of forming metal derivatives, as outlined above, is also applicable to metals other than the alkali or alkaline earth group. The desired metal alcoholates are formed by double decomposition of alkali alcoholate with an alcohol solution of the chloride of the desired metal. This mixture can then be reacted directly with the combined thiophosphate' ester-thiolic acid reaction product described above to form the metal derivative. The alkali chloride formed as a by-product in preparing the alcoholate of the desired metal is filtered from the reaction product to give the finished material.

The metal salts contemplated herein :are illustrated by the following examples.

EXAMPLE 3 Barium salt of the thiophosphate ester-thiolic acid of wax-phenol carbowylic acid (3-14) (a)Reaction mixture:

' Grams Thiophosphate ester-thiolic acid of waxphenol carboxylic acid (3-14) in solution in 300 grams of mineral oil (67 secs. S. U. V. at 210 F.) 100 Benzol '200 Ba(OH)2.8H2O 37 b) Procedure:

acid-(344), is approximately a 25%, solutionin mineral oil, and is characterized by the representation,

lo a.

wherein Rm is wax.

Exmtr 4 (a) Reaction mixture: Thiophosphate ester-thiolic acid of wax-phenol carboxylic acid (3-14) in solution in 300. grams of mineral oil (67 secs. 8. U. V. at 210 F.) g a grams... 100. Butanol cc 200 Metallic sodium grams 6 Stannous chloride do 24.8,

(11) Procedure:

The mineral oil blend containing the combined thiophosphate ester-thiolic acid of wax-phenol carboxylic acid (3-14), obtained in'Example 1, is diluted with 100 cc. of butanol. Sodium, in the form of thin strips, is then added and the mixture is heated at the reflux temperature until all of the sodium has reacted. Stannous chloride in solution in butanol is then added and the reaction mixture heated at reflux for about minutes. Butanol is distilled from the reaction mixture and the butanol-free mixture is then cooled, diluted with benzol and filtered. The filtrate is then distilled to remove benzol therefrom to obtain a mineral oil blend of the finished product, the combined thiophosphate ester-stannous thiolate of wax-phenol carboxylic acid (3-14) which is characterized by the representation,

wherein Rm is wax.

Ex'lmru: 5

Barium salt of the thiophosphate ester-thiolic acid of wax-phenol carboxylic acid disulflde (a) Reaction mixture:

, Grams Thiophosphate ester-thiolic acid of waxphenol carboxylic acid disulfide (3-14) in solution in 300 grams of mineral oil (6'? secs. S. U. V. at 210 F.) 37

amonnamo (b) Procedure:

The method of preparation is the same as in Example 4 and the finished product in this case is characterized by the representation the present inventors, o. M. Reifi, was reacted with P285, in mol proportion of about 2:1 and where Rnl is wax.

REACTION SALTS OF ALKYL-SUBSTITUTED HY- DROXYAROMATIC CARBOXYLIC ACIDS ANDPaSs EXAMPLEB Reaction of barium salt of diiamyl-phenol carbozylic acid and PzSs (a) Reaction mixture:

. Grams Barium salt of diamyl phenol carboxylic acid in solution in 50 grams of mineral oil-(67 secs. S. U. V. at 210 EL- 50 Be'naol 50 P255 12.8

OF ALKALINE EARTH METAL reaction of said acid with PzSt. The benzol is then distilled from the reaction mixture'and the temperature is raised thereafter. to 125 C.-, and maintained for several hours to remove the H28 formed in the reaction. The finished product, the combined thiophosphate ester-barium 'thiolate of diamyl phenol carboxylic acid; is thus obtained in a 1:1 oil blend, and ischaracterized by the representation ExAmPLs'I Reaction of barium salt of wax-phenol carboaylic acid disulfldie (3-14) and P285 (b) Procedure:

The barium salt of wax-phenol 'carboxylic acid disulflde (3-14), in mineral oil blend, prepared the reaction product worked .up' as described in Example 6 above. The final reaction product is presumably the same as the final reaction product obtained in Example 5, namely, the thiophos phate ester-barium thiolate of wax-phenol carboxylic acid disulfide; and, therefore, the formula given in Example 5 also represents the reaction product obtained in this example.

REACTION OF ALKALI .IVIETAL SALTS OF A L K Y L SUBSTITUTED H YDROXYARO- MATIC CARBOXYLIC ACIDS AND P285 EXAMPLE 8 Reactioa of sodium carboxylate salt of diamylphenol carbon lie acid and P285 (a) Reaction-mixture:-

" Grams Sodium carboxylate salt of diamylphenol carboxylic acid in 100 grams of .mineral oil (67 secs. S. U. V. at

Benzol 100 P285 (b) Procedure:

The procedure here is the same as in Example 6 and the final reaction product corresponds to the combined thiophosphate ester-sodium thiolate of diamyl-phenol carboxyl'ic acid which may be represented by the formula uCs To demonstrate the efiectiveness of these compounds or reaction products obtained by the reaction of substantially two mols of an alkyl-substituted hydroxyaromatic carboxylic acid and one mol of P285, and the metal salts thereof, in mineral oil compositions, we have conducted several comparative tests with representative mineral oils alone and with the same oils'blende'd with typical compounds or reaction products of the class contemplated herein. These tests, which with their results are described below, show that mineral oil compositions containing these materials are improved as to pour point, viscosity index, and acidity during engine operation.

Pour point depression The oil used in this test was a mineral lubricating oil fraction having a Saybolt Universal as described in Patent 2,256,443, issued to one of the pour point of the oil.

I 2,386,206 A Y i TABLE 1 A. S. 'l. M. pour point, 6F I Improving agent None +20 Combined thiosphospliate estcrthlolic acid of wax-phenol carboxylic acid (3 14) +20 0 15 15 Barium salt +20 (obalt salt 0 l0 -'20 Tin salt +21) 5. -15 20 Calcium salt... +20 0 -l5 -20 Combined thiophosphate este lic acid of wax-phenol carboxylic acid disulfide (3-14) +20 0 0 Barium salt +20 0 10 20 Vzscoszty index The results tabulated below in Table 2 demon strate the comparative efiectiveness of the reaction products or compounds contemplated herein as improvers of the viscosity index (V. I.) of

motor oils. The oil used in these tests was a motor lubricating oil fraction having a kinematic viscosity of 30. l7 and 4.80 at 100 F. and at 210 F., respectively, and a viscosity index of 79.8. It is apparent from these results that the oil improving agents of this invention efiect an ,appreciable improvement in the viscosity index of the oil.

TABLE 2 Kinematic vis- 7 Cone eosity, centi- Improving agent blended with by stokes, atv I motor oil weight None 0 so. 17 a s 79.8 Combined thiophosphate esterthiolic acid of wax-phenol carboxylic acid (3-14) l 33. 10 5. 10 85. 0 Barium salt 1 37. 22 5. 63 97. 2 'Iin salt... 1 31. 67 4. 99 86. 0 Cobalt salt. 1 32. 02 5. O0 84. 2 Calcium sal 1 31. 78 4. 97 83. 3 Combined t phosphat esterthiolic acid of wax-phenol carboxylic acid disulfide (3-l4). 1 31. 98 4. 98 82. 6 Barium salt l 33. 06 5. l3 0 Operation test We have also made comparative tests between an oil and oil blends containing representative improving agents of the type contemplated herein to determine the comparative behavior of the unblended oil and the improved oil under the actual operating conditions of an automotive engine. In order to determine the comparative effectiveness of an oil blend of the type contemplated herein, namely, one containing a metal salt prepared by using the aforesaid molar ratio of one mol of P285 to two mols of an alkyl-substituted hydroxyaromatic carboxylic acid, and of interval of either 16, 24 or 36 hours with the cooling medium held at a. temperature of about 212 F. and the oil temperature held at about 280 F. The engine was operated at a speed of about 1830 R. P. M. .At the end of the test .the oil was tested for acidity (NIN). and viscosity.

The oil used in the test was a lubricating oil having a kinematic viscosity of 5.8 centistokes at 210 "F. The results on the blank oil and the oil blends are listed in Table 3 below.

TABLE 3 Hrs.

Kinematic vis. at

Concf,

Improving agent blended percent 1 with motor oil None 8.68 Combined thio hosphate ester-thiolic so! of waxphenol carboxyllc acid 0.25 as it The data tabulated in Table 3 clearly show that the improving agents of this invention efiect substantial improvement in mineral oil during actual operating conditions. Such data also show the superiority of these improving agents over related materials obtained by using a different molar ratio of reactants, namely, one mol of P285 to four mols of an alkyl-substituted hydoxyaromatic'carboxylic acid (or metal carboxylate thereof).

It will be apparent from the foregoing description that we have developed a new class of mineral oil compositions characterized by the presence of a minor proportion of a combined thiophosphate ester-thiolic acid of an alkylated hydroxyaromatic carboxylic acid, which is obtained by the reaction of substantially two mols of an alkylated hydroxyaromatic carboxylic acid and one mol of phosphorus pentasulfide, and the metal salts thereof. Itis to be understood that theproperties of the added agent may be varied by the degree of alkylation and the substituent groups on the aromatic nucleus in addition to the oil-solubilizing alkyl, thiophosphate ester, and

thiolic acid (or metal thiolate) groups. It will be further understood that the improvement effected inthe mineral oil composition may be varried by the amount of agent added. In general, it appears that the desired improvement can be effected by amounts varying from about 1 6 of one per cent to about 10 per cent, but the invention contemplates the use in amounts varying from of one per cent to 2 per cent.

- We claim:

1. An improved mineral oil composition comprising a mineral oil fraction having in admixture therewith a minor proportion, sufllcient to stabilize said oil fraction against oxidation, of a compound characterized by the presence-of an aromatic nucleus containing at least one oil-solubilizing alkyl group, a thiophosphate ester group consisting of a thiolic acid group and a metal 2. .An improved mineral oil composition comprising a mineral oil fraction having in admixture therewith a minor proportion, sufiicient to stabilize said 011 fraction against oxidation, of a compound charatcerized by the presence of an aromatic nucleus containing at least one oil-solubilizing alkyl group having at least twenty carbon atoms, a thiophosphate ester group (-OPOS), and a group selected from the group consisting of a thiolic acid group and a metal thlolate group (COSX) wherein X is selected from the group consisting of hydrogen and at least one metal equivalent, said compound being obtained by the reaction of substantially two mols of a compound selected from the group consisting of an alkylsubstituted hydroxyaromatic carboxylic acid and an alkyl-substituted hydroxyaromatic metal carboxylate, the alkyl substituent being at least one oil-solubilizing alkyl group having at least twenty carbon atoms, and one mol of phosphorus pentasulflde.

3. An improved mineral oil composition comprising a mineral oil fraction having in admixture therewith a minor proportion, sufllcient to stabilize said 011 fraction against oxidation, of a compound characterized by the presence of an aromatic nucleus containing at least one oil-solubilizing alkyl group of the type which characterizes petroleum wax, a thiophosphate ester group OPOS), and a group selected from the group consisting of a thiolic acid group and a metal thlolate group (-COSX) whereinX is selected from the group consisting of hydrogen and at least one metal equivalent, said compound being obtained by the reaction of substantially two mols of a compound selected from the group consisting of an alkyl-substituted hydroxyaromatic car boxylic acid and an alkyl-substituted hydroxyaromatic metal carboxylate, the alkyl substituout being at least one oil-solubilizing alkyl group of the type which characterizes petroleum wax,

and one mol of phosphorus pentasulfide.

4. An improved mineral oil composition comprising a mineral oil fraction having in admixobtained by the reaction of substantially two molsof a compound selected from the group consisting of an alkyl-substituted hydroxyaromatlc carboxylic acid and an alkyl-substituted hydroxyaromatic metal carboxylate, the alkyl substituent being at least one oil-solubilizing alkyl group, and one mol of phosphorus pentasulfide.

5. An improved mineral oil composition comprising a mineral oil fraction having in admixture therewith a minor proportion, suflicient to stabilize said 011 fraction against oxidation, or a compound representedby the formula o O-P=S R..'rcosx wherein T is an aromatic nucleus; X is selected from the group consisting of hydrogen and at least one metal equivalent; R is at least one oilsolubilizing alkyl group; 11. is the number of said R groups and is a small whole number from 1 to 4; said compound being obtained by the reac-.

' prising a mineral oil fraction having in admixture therewith a minor proportion, suflicient to stabilize said all fraction against oxidation, of a compound represented by the formula R"[T(OPOS) (COSX) ]u [T(OPOS) (COSX) attached to said alkyl group R" through the valence 1); said compound being obtained by the reaction of one mol of phosphorus pentasuliide and substantially two mols of a compound selected from the group of compounds consisting of an alkyl-substituted hydroxyaromatic carboxylic acid and an alkyl-substituted hydroxyaromatic metal carboxylate, the alkyl substituent of said compound being at least one oil-solubilizing alkyl group.

. '7. An improved mineral oil composition comprising a mineral oil fraction having in admixture therewith a minor proportion, sufllcient to stabilize said oil fraction against oxidation, of a compound represented by the formula v R"[T(OPOS) (COSX) lu wherein R represents at least one oil-solubiliz- .ing alkyl group having at least twenty carbon atoms, attached by one valence only to at least one aromatic nucleusT; 1: represents the valence of said alkyl group R and is a small whole numher from 1 to 4; X is selected from the group consisting of hydrogen and at least one metal equivalent; u is a small whole number from 1 to '4 and represents the total number of groups [T(OPOS) (COSX) attached to said alkyl group R throu h the valence 12; said compound being obtained by the reaction of one mol of phosphorus pentasulfide and substantially two mols of a compound selected from the group of compounds consisting'of an alkyl-substltuted hydroxyaromatic carboxylic acid and an alkyl-substituted hydroxyaromatic metal carboxylate, the alkyl substituent of said compound being at least one oil-solubilizing allwi group having at least twenty carbon atoms.

8. An improved mineral oil composition comprising a mineral oil fraction having in admixture therewith a minor proportion, suiiicient to stabilize said oil traction against oxidation, of a compound represented by the iormula wherein R represents at least one oil-solubilizing alkyl group of the type which characterizes petroleum wax, attached by one valence only to at least one aromatic nucleus T; 1) represents the valence of said alkyl group R and is a small whole 7 [T(OPOS) (COSX) attached tosaid alkyl group R" through the valence u: said compound being obtained by the reaction of one mol of phosphorus pentasulfide and substantially two mols of a compound selected from the group of compounds consisting of an.

alkyl-substituted hydroxyaromatic ,carboxyiic acid and an alkyl-substituted hydroxyaromatic metal carboxylate, the alkyl substituent of said compound being at least one oil-solubilizing group of the type which characterizes petroleum wax.

9. An improved mineral oil composition comprising a mineral oil fraction having in admixture therewith a minor proportion, suflicient to stabilize said oil fraction against oxidation, of an intimate mixture of oil-soluble alkyl-substituted aromatic compounds obtained by the reaction of one moi of phosphorus pentasulfide and substantially two mols of a compound selected from the group consisting of an alkyl-substituted hydroxyaromatic carboxylic acid and an alkylsubstituted hydroxyaromatic metal carboxylate, and monoand poly-sulfides of said carboxylic acid and of said metal carboxylate, said oil-soluble aikyl-substituted aromatic compounds of reaction being characterized by the presence of a thiophosphate ester group (-OPOS), of a group selected from thegroup consisting of a thiolic acid group and a. metal thiolate group (-COSX) wherein X is selected from the group consisting of hydrogen and at least one metal equivalent, and of at least one oil-solubilizing alkyl substituent, and said compounds differing from each other with respect to the nature of said alir'yl sub-' stituents which are comprised essentially of all-- phatic hydrocarbon groups corresponding substantially to the diiierent aliphatic hydrocarbons contained in paraflln wax.

10. An improved mineral oil composition comprising a mineral oil fraction having in admixture therewith a minor proportion, sufficient to stabilize said oii fraction against oxidation, of

an intimate mixture oi. oil-soluble alkyl-subst'ituted aromatic compounds obtained by the reaction of one moi of phosphorus pentasulfide'and substantially two mols of an alkyl-substitu'ted hydroxyaromatic carboxylic acid, said oil-soluble alkyl-substituted compounds of reaction being characterized by the presence of a thiophosphate ester group (-OPOS), or a thiolic acid group (-COSH), and of at least one oil-soiubilizing alkyl-substituent. and said compounds diflering from each other with respect to the nature of said aiiryl substituents which are comprised essentially of aliphatic hydrocarbon groups corresponding substantially to the diflerent aliphatichydrocab bons contained in paraiiin wax.

11. An improved mineral oil composition comrising a mineral oil fraction having in admixture therewith aminor proportion, sufllcient to stabilize said all fraction against oxidation, of an intimate mixture of oil-soluble alkyl-substituted aromatic compounds obtained by the reaction of one moi of phosphorus pentasuliide and substantially two mols of an alkyl-substituted hydroxyaromaticpmetai carboxylate, said oil-soluble alkyl-substitutcd aromatic compounds oi reactionbeing characterized by the presence or a .thiophosphate ester group (OPOS), of a metal thiolate group (-COSM), and of at least one oil-solubilizing alkyi substituent, and said compounds differing from each other with respect to the nature of said aikyl substituents which are comprised essentially of aliphatic hydrocarbon groups corresponding substantially to the diflerent aliphatic hydrocarbons contained in paraflin wax.

12. An improved mineral oil composition comprising a mineral oil fraction having in admixture therewith a'minor proportion, suflicient to stabilize said oil fraction against oxidation, of an intimate mixture of oil-soluble aikyl-substituted aromatic compounds obtained by the reaction of one mol of phosphorus pentasulflde and substantially two mols oi a disuliide of an alkylsubstituted hydroxyaromatic carboxylic acid, said oil-soluble alkyl-substituted aromatic compounds of reaction being characterized by the presence of a thiophosphate ester group (-OPOS oi a thiolic acid group (-COSH), and of at least one oii-solubilizing alkyi substituent, and said compounds diifering from each other with respect to the nature of said alkyl substituents which are comprised essentially of -aliphatic hydyrocarbon groups corresponding substantially to the diflerent aliphatic hydrocarbons contained in paramn wax.

13. An improved mineral oil composition comprising a mineral oil fraction having inadmixture therewith a minor proportion, sufllcient to stabilize said oil fraction against oxidation, of a thiophosphate ester-barium thlolate oi diamyl phenol carboxylic acid.

- JQHN J. GIAMMARIA.

ORLAND M. REIFF. 

